Specifically workflows involving Quicktime. I'm having problems. Automator Runner won't launch them as it is supposed to (I use iCal alarms to open Automator Runner files) and Quicktime now goes through a different save file process. Anyone else having issues?

I put a call into Apple, they weren't aware of the problem and really couldn't do anything to help us out at this early stage, but at least it is documented with them as being an issue. Hopefully its something addressed in a future update or somebody around here with more skills then myself figures out the problem.

Helpful tip in case anyone comes across this thread: If you have workflows that include the "Launch Application" or "Quit Application" actions with iCal, Address Book, or iChat, the app names in Mountain Lion are now called Calendar, Contacts, and Messages, and your workflows won't automatically update themselves. You'll need to open them and choose the new app name(s).

Well after some tinkering, I think I've found a solution. When you start Automator and it asks you if you want the action to be a workflow, iCal alert, etc. Select the Application option, so the workflow is created as an Application. You can also convert an existing workflow to an Application in the Automator menu go File>Convert To...

Then in Calendar when you create the event, have a Calendar alert to Open said file and abracadabra, it runs at the right time! It pretty much bypasses using Automator Runner, for whatever reason having the action as an Application is different. I've only tested this on actions involving moving files to various folders and deleting things though.